1. Field of the Invention
The present invention relates to an address information registering/searching system in a network system in which a plurality of stations are connected to a trunk network, each station includes a network adaptor, and nodes are connected to some of the stations via branch networks and, more particularly, to an address information registering/searching system suitable for address information searching required for data transfer between nodes, and between a node and a station.
2. Description of the Related Art
As shown in FIG. 1A, a branch frame used in data transfer in a branch network includes a branch destination node address field BDA, a branch source node address field BSA, and a branch data field BDATA. In a network system in which branch networks are connected to a trunk network via network adaptors of stations, when data is to be transmitted from a source node in a certain branch network to a destination node in another branch network, a destination node address, a source node address, and data to be transmitted are written in the fields BDA, BSA, and BDATA, respectively, of the branch frame, as shown in FIG. 1B. Such a branch frame is transmitted from the source node to a source branch network to which the source node is connected. A source network adaptor normally monitors the branch frame on the source branch network. When the source network adaptor receives the branch frame, it cancels the branch frame if a destination address designated by a destination node address in the branch frame belongs to intra-branch-network. If the destination node does not belong to the intra-branch-network of the source network adaptor, the source network adaptor forms and transmits a trunk frame onto a trunk network. As shown in FIG. 1C, a destination branch address, a source branch address, and the branch frame shown in FIG. 1B are written in a trunk destination branch address field TDA, a trunk source branch address field TSA, and a trunk data field TDATA, respectively, of the trunk frame.
The trunk frame on the trunk network is received by a destination network adaptor at a station to which a branch network designated by the destination branch address written in the field TDA is connected. When the destination network adaptor receives the trunk frame on the trunk network, it transmits a portion of the field TDATA onto its own branch network. The branch frame on the destination network is received by a node designated by the destination node address written in the field BDA.
In this manner, the branch frame is transmitted from the node connected to the branch network in a certain station to the node connected to the branch network in another station. In this transmission, the source network adaptor must know a branch address of the branch network to which the destination node designated by the destination branch node address written in the field BDA belongs. A conventional network adaptor has an address table which registers address information by a hash system. The address information includes a pair of a node address for designating a node and a branch address of a branch network to which the node belongs. In transmission using the trunk network, the source network adaptor searches for the address table and obtains the destination branch address of the branch network to which the destination node belongs in accordance with the destination address. In this case, if a large number of address information having the same hash value are linked by a pointer or the like, it takes a long time period to find out address information including an object address pair.